Update the parent data when user navigates to a specific route path - vue.js

Question

I'm new in VueJs, trying to set up a web application with Vue-route, and want to update the <header> style when user navigates to a specific URL, whether using "URL bar" directly or "navigation bar". In this case, we have a parent component that contains height_status data and some <router-links> on template.
I've done the "navigation bar" part with $emit technique and it works well but then I've tried to use it on created lifecycle hook in order to update the header whenever the /home route is created but event listener will not reach the parent_component.
How can I solve this? Is there a better way to do that?
Please see the code below:
Parent_component.vue
<template>
<div id="app">
<router-link to="/home" #height_size_ctrl="change_height">Home</router-link>
<router-link to="/about">About us</router-link>
<router-link to="/contact">Contact us</router-link>
<header :class="height_status ? 'head-h-s' : 'head-h-m'"></header>
<router-view/>
</div>
</template>
<script>
export default {
name: "Parent_component"
},
data() {
return {
height_status: false
}
},
methods: {
change_height(h) {
this.height_status = h
}
}
}
</script>
router.js
Vue.use(Router)
export default new Router({
routes: [
{
path: '/home',
name: 'home',
component: Home
},
{
path: '/about',
name: 'about',
component: about
},
{
path: '/contact',
name: 'contact',
component: contact
}
]
})
home.vue
<template>
<h1>hello</h1>
</template>
<script>
export default {
name: 'home',
created: function(){
return this.$emit("height_size_ctrl", true)
}
}
</script>

Answer 1

You could also change the router:
router.js
{
path: '/home',
name: 'home',
component: Home,
meta: {
headerClass: 'head-h-s'
}
}
In your component
Parent_component.vue
computed: {
headerClass() {
return this.$route.meta.headerClass
}
}
Now headerClass is available in the template.
<header :class="headerClass"></header>

Answer 2

why don't you try class binding on route or route name something like:
<div :class="{'height_status': this.$route == '/home'}">Header</div>
or
<div :class="{'height_status': this.$route.name == 'Home'}">Header</div>

Answer 3

As #kcsujeet said, class binding is the good way we can do this. In this case we need to look at the condition this.$route.path. if value is equal to the /home select 'head-h-m, otherwise select .head-h-s.
<header class="head-sec" :class=" this.$route.path == '/home' ? 'head-h-m' : 'head-h-s'">
Also we're able to access other route defined properties using this.$route. I suggest take a look at the router.js file.
routes: [
{
path: '/home',
name: 'home',
component: Home
}